![]() ![]() We will discuss more about these software applications later on as well. To convey images and graphics, commercial stations use radio-facsimile (FAX), while amateur stations use slow scan TV (SSTV) and EasyPal. Text messages are usually conveyed with these protocols. These modes - developed by amateur radio operators - use low power, complex coding, and allow communication over great distances. Some of the popular newer modes are Binary Phase Shift Keying (BPSK), Weak Signal Propagation Reporter (WSPR), and the weak signal digital modes JT65/9. Most of this application software can also decode the newer modes. The good news is that they are free and can be downloaded from the Internet. Several software decoding packages will be discussed later to help you get started with these modes. Some are as simple as Morse code (CW) or Radio-teletype (RTTY), while others are more sophisticated, such as AMTOR or SITOR which are similar to RTTY. A Closer Look at Data Modesĭata transmissions vary in complexity and contain a wide variety of information. In this article, I will show you how to use these Web based shortwave receivers to access data transmissions and to get started in this exciting hobby. However, as will be discussed later on, it does require a special trick to allow you to pipe the streaming audio signals from the Web to the decoding software. Fortunately, there are plenty of unencrypted data signals around to keep us busy for a long time. Yes, some signals are encrypted, and can’t be decoded. Now, the concept takes on a new dimension since we are using virtual radios not in our possession.Īs astonishing as it seems, many of these Web based shortwave receiver data signals can be processed and decoded using just your PC and some free decoding software. It is the realm of audio data transmissions.Ī while back, I discussed how to receive data signals with a low cost shortwave radio ( N&V May 2015). This is the other world of shortwave radio one that does not use conventional sounds. The unconventional sounds you are hearing are probably data signals. There may be warbles, buzzes, and whistles that seem to vary and repeat. When tuning through the bands - as with any shortwave radio - you will discover that there are some audible sounds that do not make immediate sense. So, bear this in mind when you are receiving signals from the remote location. However, you need to be aware of time differences that may affect radio propagation.įor example, when it is daylight in your location it may be night at the other location. It’s definitely fun to hear the music and voices of these far off lands received from their own backyard. Operating a radio located in another country can be both exciting and challenging. Using such a radio is truly incredible since you are operating it remotely from your own vantage point via the Web. A screenshot of a web based SDR located in Sweden is shown in Figure 2.įIGURE 2. Two popular places to find these Web radios are and SDR.hu. The dial frequency, mode (AM, SSB), audio bandwidth, and other features of the receiver are fully controlled by you. Each location has its own antenna, receiver, and connection to the Internet. If you’ve ever wanted to operate a receiver located in Sweden, Germany, Australia, Andorra, or Africa, now is your chance. World map of Web based software defined radios. ![]() Even more remarkable is that they are located in countries all around the world.Īn example of the worldwide spread of SDR radios is shown on Figure 1.įIGURE 1. These SDRs are free to use and widely available on the Internet. Web based shortwave radios are an amazing new implementation of software defined radios (SDR). ![]() So, read on and we’ll guide you through the details of how to do it. Unfortunately, employing these radios to decode data transmissions can be very difficult or impossible - unless you know the secret. Your computer and the Internet give you free access to over 100 web based shortwave receivers that you can use as if they were your own. ![]()
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